Could component blueprint Thot be made optional?

[keckler]

The fact that the Thot attribute of component blueprints is mandatory has always seemed a bit odd to me.

Wouldn't it be possible to just resolve Thot to Tinput if the user doesn't enter a Thot value? Tinput is obviously definitely necessary. But there seem to be at least a couple common scenarios when Thot isn't really needed:
(1) when a user is running thermal-hydraulics calculations as part of their simulation, so the component temperatures will be updated anyways
(2) when a model is room temperature, so Thot == Tinput for every single component

Adding in some logic to resolve Thot to Tinput when the user doesn't explicitly input Thot would appear to be easy to do, and it could help cut down on the size of blueprints files by a decent chunk.

[john-science]

Would it be hard to make it clear to people that Thot is assumed if not entered explicitly?

[keckler]

As far as I can tell, the only place that we ever tell the user what Thot means is here: https://terrapower.github.io/armi/user/inputs/blueprints.html#defining-a-component

We could easily add a sentence to that description about the assumption.

[keckler]

At to the list of places where Thot is not needed:
(3) When the material is Void, which has no material properties or isotopics